Ulipristal acetate is more effective than the widely used levonorgestrel in preventing pregnancy at any point within 5 days of unprotected intercourse, according to findings published Jan. 29 in the Lancet.
Researchers led by Dr. Anna Glaser, of the National Health Service in Edinburgh performed their own study of nearly 2,000 women in Europe and the United States and also analyzed findings from a previous study.
Though neither study was of sufficient size to demonstrate the superiority of ulipristal acetate over levonorgestrel, Dr. Glaser and her colleagues wrote, combining the data from both studies showed that ulipristal acetate “almost halved the risk of becoming pregnant compared to levonorgestrel in women who received emergency contraception within 120 hours,” (1.3% vs. 2.2%). The risk was reduced by nearly two-thirds when women presented within 24 hours (0.9% vs 2.5%), the investigators wrote.
“Only when we put the two studies together were we able to demonstrate superiority,” said Dr. Glaser in an interview.
In the multisite study, 1,899 women who presented requesting emergency contraception at family planning clinics in the United Kingdom, Ireland, and the United States were assigned to a single dose of either ulipristal acetate 30 mg (n = 941) or levonogestrel 1.5mg (n = 958).
Ulipristal acetate is manufactured by HRA Pharma, which funded the study. Lovonogrestrel is made by Shering.
Of the 1,696 women who had presented within 72 hours of intercourse, there were 15 pregnancies in the ulipristal acetate group (1.8% of 844 women) and 22 in the levonorgestrel group (2.6 % of 852). Among the 203 women who received emergency contraception after 72 hours, there were three pregnancies, all in the levonorgestrel group.
Patients ranged in age from 16 years to over 35; they were not told which drug they had received. Follow-up with pregnancy testing began within a week after the expected onset of next menses.
The 1,899 women in the analyzed group were those remaining from a total of 2,221 who had presented to the family planning clinics. Excluded from study were those who were older than 35, who were lost to follow-up, pregnant when presenting, who re-enrolled in the study, or whose pregnancy status was unknown following treatment.
The authors also analyzed findings from a 2006 randomized controlled trial comparing ulipristal acetate to levonorgestrel in 1,546 efficacy-evaluable women, all of whom had presented within 72 hours of intercourse (Obstet. Gynecol. 2006;108:1089-97). There, too, the pregnancy rate was lower for ulipristal – 7 pregnancies out of 773 patients (0.9%) and 13 out of 773 (1.7%) for levonorgestrel. The European Medicines Agency approved ulipristal acetate in May 2009 for preventing pregnancy up to 120 hours after intercourse; levonorgestrel is approved only for up to 72 hours after intercourse. Levonorgestrel remains the far more widely available drug, offered at pharmacies without prescription in many countries and often free of charge. However, Dr. Glaser said, “if you really wanted to prevent a pregnancy you may decide it’s worth the inconvenience to get a doctor’s prescription for the drug that is more effective.”
Among the 13 study’s authors, three— including Dr. Glaser, report having received lecture honoraria from HRA Pharma, the manufacturer of ulipristal acetate and the study’s source of funding. Three authors are current employees of HRA Pharma; one is a former employee and a stockholder; another reports having received consulting fees from HRA; and five report no conflicts of interest.
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据1月29日发表于《柳叶刀》(The Lancet)上的一项研究结果，与广泛应用的左炔诺孕酮相比，无保护性交后5天内任何时间使用醋酸ulipristal均可达到更好的避孕效果。
由爱丁堡英国国民卫生保健(NHS)的Anna F. Glasier博士领导的研究者们对来自欧洲和美国的近2,000名女性进行了她们自己的研究，与此同时，她们还对先前的一项研究结果进行了分析。
尽管这两项研究的样本量均不足以证明醋酸ulipristal优于左炔诺孕酮，Glasier博士及其同事写道，但结合这两项研究的数据表明，醋酸ulipristal“和左炔诺孕酮相比，可使120h内紧急避孕的女性怀孕的风险减半，” (1.3% 对 2.2%)。如果女性在24h内服药，则这一风险将会下降近2/3(0.9% 对 2.5%)，研究者写道。
“只有当我们将这两项研究联合起来时，才能证明这一优势的存在，” Glasier博士在一次访谈中指出。
在这项多中心研究中，来自英国、爱尔兰和美国计划生育诊所的1,899名要求进行紧急避孕的女性被分配服用单剂醋酸ulipristal30mg(n = 941)或左炔诺孕酮1.5mg(n = 958)。
醋酸ulipristal的生产商是HRA制药公司，该公司为本研究提供了资助，左炔诺孕酮由先灵葆雅公司生产。
共有1,696名女性在性交后72h内进行了紧急避孕，其中醋酸ulipristal组有15人怀孕(占844名女性的1.8%)，左炔诺孕酮组有22人(占852人的2.6 %)。在性交72h后进行紧急避孕的203名女性中，共有3人怀孕，全部来自左炔诺孕酮组。
患者年龄介于16岁~35岁以上；她们并未被告知自己服用了何种药物。在预期下次月经来潮后1周内，研究者开始对患者进行随访调查和妊娠检测。
分析组的1,899名女性是从总计2,221名向计划生育诊所提出要求的女性中筛选所得。被排除在研究之外的女性包括年龄大于35岁者、失访者、提出要求时已怀孕者、重复被本研究招募者或那些在服药后怀孕状况未知者。
研究者还对一项2006年进行的随机对照试验的结果进行了分析，该试验对1,546名可评估药效的女性进行了醋酸ulipristal和左炔诺孕酮的对比研究，这些女性在性交后72h内均请求紧急避孕(Obstet. Gynecol. 2006;108:1089-97)。在这项研究中，ulipristal组的受孕率同样更低——773例患者中仅有7人怀孕(0.9%)，左炔诺孕酮组773例患者中有13人怀孕(1.7%)。欧洲药品管理局在2009年5月批准醋酸ulipristal用于性交后120h的紧急避孕；而左炔诺孕酮仅被批准用于性交后72h。左炔诺孕酮依旧是使用范围远为广泛的药物，在许多国家无需处方即可在药房获得该药，并常常是免费的。然而，Glasier博士说，“如果你真想终止一次妊娠，你需要考虑，是否值得忍受麻烦去向医生索取这一更有效药物的处方。
在本研究的13位作者中，有3位——包括Glasier博士，报告曾接受了来自HRA制药公司的演讲酬金，该公司是醋酸ulipristal的制造商及本研究的资金来源。有3位作者目前是HRA制药公司的雇员；还有1位作者是该公司的前雇员及股东；另1位作者报告曾接受了HRA公司的咨询费；有5名作者声明无利益冲突。
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